Inclosed tumbler switch



Oct.. 13, 1931; G. A. JOHNSON I INCLOSED TUMBLER SWITCH Filed May 17, 1928 Suva/mtu GEORGE A. JOHNSON' Patented oa. 13, 1931 UNITI-:o STATI-:s rA'raNr ori-Ica GEORGE A. JOHNSON, F FAIBFIIIELD, CONNECTICUT, ASSIGNOR 'ITO THE BRYANT ELEC- TBIC COMPANY,A 0F BRDGEPORT, CONNE(T1CUT, A. CORPORATION 0F CONNECTICUT mcLosEn manna swIrcH .Application med my 17.1928. semina. 278,447.

This invention relates to electric switches and in particular to the types known as snap and tumbler switches.

The objects of the invention are (1) to simplify and to economize the constructionl of the switch movement and of the housing therefor, (2) to render the operation of the switch vmore nearly silent than has heretofore been possible, (3) to make the operation Aof E0 the switch quick and certain.

The preferred embodiment of the invention is illustrated in the accompanying draw- ,.in s and .is described hereinafter.

' n the drawings- Fig. 1 is a top plan view of the switch with the cover in place;

Fig. 2 is a sectional view on4 the line 2-2 of Fig. 1; l

Fig. 3 is a plan view of the interior of the 30 switch base with the cover and switch movement removed;

Figs. 4 and 5 are end views of the interior ofthe base on the lines 4 4 and 5-5 respectively of Fig. .3;

Fi g. 6,is a view in section on the line 6-6 of Fig. 2';

. Fig. 7 is an exploded view on an enlarged scale, of a part of the switch movement;

Fig..8 is a detail'perspective view of the connectionbetween a movable'contact member and its carrier; f

Fig. 9 isa rspective view of the bridge member forming part of the switch movement; Fig. 10 is piece.

l The switch comprises three main parts, the base 11, the cover 12 and the switch move ment.

The base 11 is of insulating material and has a well for the switch movement. On the corners of the base at the open end of the well are bosses 14 and, at the mid-portions of its opposite ends, larger bosses 15, these bosses serving'to position the cover. The inner bottom surface of the base is recessed at 16 to permit rocking of the contact carrier.

At one end of the base are fixed terminals 17 and 18 held in place b`y screws 19, 20 exa perspective view of the thumb 0 tending through the wall. of the base from the underside. The terminal piece 17 has a portion 21 extending upwardly and inwardly to forni a knife-blade contact. Piece 18 has asimilar portion 22 extending downwardly in the well 1n the base and inwardly as shown 1n Fig. 2.

At the other end of the base are terminals 23, 24 held in place. by screws 25, 26 similar to screws 19, 20. rh'ese terminals are connected by a ortion 27 which lies in the well and has an-o set portion forming a contact blade 28. Extendinginwardly and upwardly in the same manner as 21 is a contact blade 29.

Each terminal piece has a binding screw 30 for securing a lead wire.

The cover 12 is of moldableinsulating material and is hollow. The ends of the cover are shaped to fit the bosses 15 and have shoulders to rest against the bosses 14. The cover has an aperture 31 -or the thumb-piece and slots for the contact blades 21 and 29.

The cover is held in position by ears 32 which serve also as a meansfor attaching the switch to a wall box, face plate or other support which commonly is used with switches of this type. For this latter purpose, holes 33 are provided in the offset attaching ortions 34 and are enlarged to permit some reedom of positioning. The ears have odsets 35 which extend ver the shoulders formed by recesses 36in the cover and' thus, when the ears are secured in position on the base by the screws 37 which extend through holes 38 from the underside of the base, the cover is held tightly on the base.

Attention is called to the fact that the cifsets 35 are bowed to give a certain resilience. This is to accommodate the slight differences in dimensions of thecover 12 and of the parts ofmthe-base which determine the relative levels of the recesses 36 and the top of boss 15. These'dierences areavoidable only at considerable expense in manufacture but by' the `present construction are rendered immaterial. The resilience of the bowed offsets also gives a tighter clamping action and serves as a lock washer to keep the screws 37 from turning. It is to be noted that the ears should be held flat against the boss 15 to assure proper positioning of the attaching osets 34 in the same plane parallel to that of the plate to which the are secured.`

The switc movement consists of a xed member having arms 41 which rest on shoulders 15 on the bosses 15 and against the sides of these bosses.- The'cross bars 42 connecting the parallel bars 43 are so spacedl that they rest snugly against the bosses .15 and on the shoulders 15. The result is that Ythe bridge piece ispositioned on the base so ls to be immovable laterally and, with the cover 12in place, itis immovable in any direction.

shape of the fulcrums is important.

' The fulcrum surfaces 45 and 49, the throat portions and the surfaces adjacent the throats and connecting the respective throats and fulcrum surfaces are curved, as shown 1n 2 and 9. The members which rock on these-fulcrums are fiat (see 52 and 63) land are limited their rocking movement by engagement on opposite sides with the curved surfaces adjacent the throats. By reason of the curves, this engagement is not sudden norv is it a direct surface upon surface engagement which would cause a noise 'as of a slap.

The engagement is gradual and to this,.as

well as to the material used for the carrier 60, described hereinaftertis attributed the silence of operation which characterizes this switch.

The rocking actuator (see Figs. 2 and 7 is, in general shape, an inverted. U. The down legs 51 have, near their lower ends, oi-

set lugs 52 which rest on the fulcrums 45 limited rocking movement on the fulcrumsformedon the downwardly extending arms of the bridge 40. Thus the actuator has a but isrestrained by throatsl 46 from excessive transverse movement. Near their upper ends, the legs 51 have oli-set or bowed portions 53 and 54 extending in opposite directions on the arcuate path of the actuator about its fulcrum for av purpose to be described. At the upper end of the actuator is a transverse member 55 having a stem on which is secured, in any known manner, a thumb-piece 56. The latter has curved shoulders 57 so that Whatever the position assumed by the roclcing actuator and thumb-piece, there is always a shield toY prevent objects from entering the portions forming throats 46.

switch by way of the 12. (See Figs.1and2 v The contact ca "er 60 is likewiseofA U sha e but wider than the actuator v50 as shown in igs. 6 and 7. Itis made of insulating material, eitherlibrous'or molded material of phenolic composition such as bakelite. Nearv the upper ends and on the inner *sides of the legs 61 of this carrier are oi-set lugs 62 from the lower portions of which extend the narrower lugs 63. Lu apart the same amount as t e bridge bars 43 on-the member 40 so that these lugs 62 rest in the fulcrum recesses 49.

. As shown in Fig. 6, the carrier Aswings about the fulcrum 49 outside-of the brid e member 40 with its transverse portion 64 c caring the down arms 44. The actuator 50, fulcrumed at 45, swings inside of the member 40 between bars 43. .A coil spring 65 connects the transverse members 64 and 5 5 of the two rocking members 50 and 60. Theveifortof the spring draws the two 4rocking members together and against their respective fulrums 45 and 49, thus holding the members in proper `position without permanent securing means.

The'lugs 63, extending inwardly from lugs 62, lie .in the path of. movement of the legs v51 of the actuator 50 ('see'Figs. 6 and 7) and adjacent the bowed portions 53 and 54 of the legs 51.

On the outer sides of the legs 61, near their upper ends butv below the to or pivot ledges of lugs 62, are apertured o -set portions 66 for receivin the switch bars, one on each side of the carrler. The width of the slot is of greater extent i than lthe thickness of the switch bar.

These switch bars 67 are stamped vfrom lconductive sheet material, each bar being made of two strips fastened together. Each bar has two arms 69, 70 and an enlarged central portionv 71, the two arms being at an angle to each other (see Figs. 2 and 7) and the central portion 1 having a rectangular slot 72 with its long axis at right angles toarm 7 0 and of a size to receive one of the off-sets or earsv 66 of the carrier 60. Each arm has at its end,.separated contact portions l(Fig. 7 4for engaging both sides of the fixed knife blade contacts in the base 11.

To secure together the strips which .make up each'switch bar 67, the following method is prefer-red. Holesv77, 78, are punched in each strip, one hole 77 being left with the punched out material outstanding-from the strip. With the other hole 7 8, the turned up 62 are spaced` 31 in the cover I material is cut away. The two strips may through the hole 78 of the other.' The ends of the turned. up portions are then spun or otherwise bent to lie over the other strip, thus firmly joining the two strips together. This l eiects aneconomy in the manufacture since all strips may be made exactly alike and by the same operation.

The switch bars 67 are secured on the carrier 60 by clips 75 (Figs. 7 and 8) which are of spring material and are bent so that when forced through the apertures in the ears 66 on the side of the switch bars away from the carrier, the central part of the clip bears against the ear and the arms 76 of the clip exert a pressure against'the switch bars holding them against the carrier 60.

This engagement between the switch bar and the carrier is such as to permit some swinging of the bars about the lugs 66 in a plane at right angles to that of the carrier. Such a oating mounting renders the bars self-aligning with respect to the lixed contacts, the flared ends 74 of the bars guiding the bars into fully 4closed position. lThis feature further simplifies the assembly in eliminating the need of greatcare and accuracy in positioning the contacts in each particular switch.

When the switch movement is assembled, the switch bars 67 are positioned with their arms parallel. Then, when in place in the base, as shown in Fig. 2, one switch bar connects the fixed contacts 28 and 21, the ixed contacts 29, 22 being disconnected. If the switch bar carrier is put in itsA other position by movement of the actuator, the fixed contacts 29, 22 are connected and the contacts 28,

'21 are disconnected.

Various changes may be made in the arrangementv of the fixed contacts or in the relative positions of switch bars. The arrangement shown is illustrative only and forms no part of the present invention.

Thefunction and operation of the several parts are apparent.

The switch movement is a singlet unit which may be removed bodily from the base 12. It requires no securing means such as screws to hold it on the base but is positioned by the bosses 15 and held by the cover 12 which rests on the cross bars 42. 1-

The cover is positioned by the corner bosses t `14 and the end bosses, 15, vand is held to the base by the ears`32 which serve also as means for attaching the whole switch to a support such as a face plate or wall box.

A The operation of the switch movement 1s responsive to movement of the thumb piece 56 and actuator 50, the spring 65 transmitting this movement tothe carrier and givlng a quick Vand certain movement of the swltch bars 67. The actuator rests normally at either end position with either pair of fixed contacts connected by a switch bar. As the actuator is moved, it carries the upper end of the spring with it'. When thisvend of the spring passes the' dead center plane deterl mined by the upper and lower pivots, 49 andv 4`5,o\nthe`ixedfbridge member 40, the effort of the spring on the rocking carrier causes the v said bar away carrier to swing about the fulcrums 49 and to snap into position against abutment 47 (assuming movement from the Fig. 2 position) thus swinging the switch bars 67 from the position in which fixed contacts 22 and 29 are connected, to that in which 21 and 28 are connected.

If, for any reason, the contacts do not separate easily under eiort of the spring 65, further movement of the actuator causes either bowed portion 53 or 54, depending on the direction of movement, to engage one of the lugs 63. By this, a positive kick-off is effected. It is to be noted that the point of application of the kick-off ei'ort is close to the pivotal axis of the carrier 60 and that, thereby, no bending of the carrier is brought about. The purpose of having the kick-off portions off-set is to delay their contact with lugs 63 until after the actuator has passed the dead-center plane where normally the spring should begin to draw on the carrier.

The use of insulating material for the carrier 60 has several advantages. Since the carrier strikes either abutments 47 or 48 on each movement, it follows that if `both the carrier and the abutments are of metal an undesirable noise is created, audible in adjacent rooms especially where the walls are thin as is often the case. When insulating material, 95 either tibi-ous or molded, is used, it is found that this noise is so slight as not to be objectionable.

' A further advantage fromausin insulating material for the carrier i` in tie simple 100 type of connection between t e carrier and the switch bars which it makes possible. If the carrier is of metal, insulating pieces must be used between it and the switch bars. These pieces add to the cost and to the diiculty of assembly.

In the present structure, insulating pieces between the carrier and the switch bars are not needed. The securing clip 75 is very quickly putin place. The cost of materials, manu- 110 facturing operations and assembly operations is therefore reduced.

In an electric switch, a off-set portion, a switch bar slotted to receive 115 said off-set portion, said portion having an aperture of greater extent than the thickness of said switch bar, and a spring clip extending through said aperture on the side of from the carrier and engaging 120 said ,barand said off-set portion to hold the carrier having an bar against the carrier.

GEORGE A. JOHNSON.

signed my 

